Field of the Invention
The present invention relates to a semiconductor device and an information processing system.
Description of the Related Art
As one of distance measurement methods, there is a TOF (Time Of Flight) method of performing distance measurement by irradiating a target object to undergo distance measurement with light from a light source and detecting the light reflected from the target object. In the TOF method, a distance to the target object is calculated based on the relationship between the speed of light and a time from irradiation with light to reception of the reflected light. Note that light (ambient light) caused by a light source different from a light source for distance measurement, such as natural light or artificial light, is superimposed on the reflected light. The influence of the ambient light needs to be suppressed in order to increase the accuracy of distance measurement.
A second embodiment of Japanese Patent Laid-Open No. 2005-303268 exemplifies a semiconductor device which includes the first photosensitive unit having a structure suitable for extracting holes and the second photosensitive unit having a structure suitable for extracting electrons. The holes generated in the first photosensitive unit by ambient light when a light source is turned off are held in a hole holding unit. The electrons generated in the second photosensitive unit by reflected light and the ambient light when the light source is turned on are held in an electron holding unit. The holes held in the hole holding unit and the electrons held in the electron holding unit are recombined in a recombining unit, a carrier generated by the ambient light is removed, and a remaining carrier is obtained as a carrier generated by the reflected light.